MONDAY, March 21 (HealthDay News) -- Affluent young white women -- who presumably have more opportunities for tanning -- are nearly six times as likely to develop the lethal skin cancer melanoma as their poorest counterparts, a new study indicates.

In research examining the relationship between melanoma incidence, ultraviolet (UV) light exposure and socioeconomic status, scientists studied data from 3,800 white girls and women in California aged 15 to 39 during two periods a decade apart.

Among those women, 3,842 melanomas were diagnosed, with diagnoses increasing most significantly over time in the three highest socioeconomic levels. UV radiation exposure was linked to higher melanoma rates only among the women in the top two levels, the study found.

"I think we originally thought that UV-sunnier areas have more melanoma . . . but it was not as powerful a predictor as socioeconomic status, and really, you need the two together," said study co-author Christina A. Clarke, a research scientist at Cancer Prevention Institute of California.

"These are young girls -- 15 to 39 -- and they shouldn't be getting cancer," she added. "Melanoma is a particularly poignant cancer, too, because it's so deadly."

The study is published online March 21 and in the July print issue of Archives of Dermatology.

Each year, melanoma is diagnosed in about 70,000 people in the United States and about 8,700 die from it, according to the American Cancer Society.

Among teens, the rate of melanoma has increased almost 3 percent a year in the last two decades, the authors noted.

Using data from the California Cancer Registry, U.S. Census and National Oceanic and Atmospheric Administration, Clarke and her colleagues zeroed in on two periods -- January 1988 to December 1992 and January 1998 to December 2002.

The researchers ranked neighborhoods in California with respect to affluence and location-specific UV exposure using Census variables such as income, education, occupations, percentage of unemployment and housing prices, Clarke said.

Girls and women in neighborhoods with the highest socioeconomic status and highest UV radiation exposure experienced 73 percent more melanoma diagnoses than those from the poorest neighborhoods with the highest UV exposure, and an 80 percent greater melanoma incidence compared to those with both the lowest socioeconomic and UV exposure.

Clarke said the researchers were unable to glean from their data whether more affluent young women were more likely to use tanning salons, but said that scenario was likely. It's also probable they take more vacations in sunny spots where sun-bathing is a leisure activity.

Dr. James Spencer, a dermatologist in private practice in St. Petersburg, Fla., agreed with Clarke's theory and said the study "is confirmation of something that's been known for years."

He cautioned parents to be diligent about protecting their children's skin while in open sun -- perhaps even more than their own.

"Melanoma correlates strongly with childhood sunburns, so we think young skin is more vulnerable," Spencer said. "For the moms and dads, your child's and teenager's skin is a lot more vulnerable than yours. Most of the damage that can lead to melanoma occurs during childhood sunburns before age 20."

Clarke and Spencer agreed that young people resist anti-tanning messages, making it particularly difficult to target them in public education campaigns.

"What do we do to make tanning less cool?" Clarke said. "I think there are a lot of messages around tanning, though I'm not sure how much melanoma has been part of this conversation. But this is serious -- melanoma can kill you."

Spencer added: "Tell a 15-year-old not to get a suntan? That's just a really hard group to reach. I think teenagers know today, but they just don't care."